Stores and gets IP address of a flow capable node

- implements RPCs get-node-ip-address from flow-node-inventory.yang
	depends on https://git.opendaylight.org/gerrit/#/c/9612/
- impelementation is done by using switch IP address from OFJava
	depends on https://git.opendaylight.org/gerrit/#/c/9615/
- stores IP address of OF capable switch to data store (depends on Bug 1585)

Change-Id: I5b46106cf94109ddddd8cf5353d749e40c43b0ec
Signed-off-by: Martin Sunal <msunal@cisco.com>